Magnesium sulfate versus fentanyl as an adjuvant with bupivacaine in supraclavicular brachial plexus block- A comparative study

Abstract

Background: Brachial plexus block is an excellent method for attaining optimal operating conditions for upper limb surgeries. This method produces complete muscular relaxation, maintaining hemodynamic stability. Objectives: The objective of the study was to evaluate the effectiveness of magnesium sulfate and fentanyl as an adjuvant to bupivacaine in supraclavicular brachial plexus block. Methods: This observational study was conducted in the Department of Anaesthesiology and ICU, Bangladesh Medical College Hospital over a period of six months after acceptance of protocol. Study populations were patients of ASA Status I–II planned for upper limb orthopedic surgical procedures under supraclavicular brachial plexus block. Study populations were randomly allocated into one of the two groups, 30 in each- group A & B. Group A - Patients received 38 ml of 0.25% bupivacaine with 100 μg (2ml) of fentanyl to make a total volume of 40 ml. Group B - Patients given 38 ml of 0.25% bupivacaine with 80mg (2ml, 4%) magnesium sulfate. Parameters observed were demographic, hemodynamics, onset, and duration of sensory and motor block, analgesia. By using SPSS, version 22.0 data were analyzed. A Chi-square test was applied for qualitative data and an Unpaired t-test was applied for quantitative data. the p-value of <0.05 was considered statistically significant. Results: In this study, there was no significant difference between groups in respect of demographic (age, gender) and ASA status (p>0.05). Regarding hemodynamics (heart rate, systolic blood pressure, diastolic blood pressure, mean arterial pressure) were no statistically significant differences between Group A and Group B (p>0.05). The onset of sensory (p=0.825) and motor block (p=0.968) was not statistically significant between the two groups. Duration of sensory and motor block was significantly increased in Group A compared to Group B (p=0.001). Duration of analgesia was no significant difference between the two groups (p=0.127). No significant difference in the total number of rescue analgesics between Group A and Group B (p=0.640). From this study, it is found that magnesium sulfate, as well as fentanyl as an adjuvant to bupivacaine, prolongs the duration of sensory and motor block in supraclavicular brachial plexus block. Conclusion: Magnesium sulfate, as well as fentanyl as an adjuvant to bupivacaine, prolongs supraclavicular brachial plexus block.